International Food Research Journal 20(4): 1537-1545 (2013) Journal homepage: http://www.ifrj.upm.edu.my Incorporation of Himanthalia elongata seaweed to enhance the phytochemical content of breadsticks using Response Surface Methodology (RSM) Cox, S. and Abu-Ghannam, N. School of Food Science and Environmental Health, College of Sciences and Health, Dublin Institute of Technology, Cathal Brugha St., Dublin 1, Ireland Article history Abstract Received: 12 February 2013 Optimization of incorporating seaweed into breadsticks was carried out using response surface Received in revised form: methodology (RSM). Ten formulations of breadsticks were processed by varying concentrations 27 February 2013 of seaweed (X = 5 to 15% of overall flour concentration) and white flour (X = 10 to 30% of Accepted:28 February 2013 1 2 overall flour concentration) using a central composite design. The remaining flour concentrations were comprised of wholemeal flour. Predicted models were found to be significant (P < 0.05) for total phenolic content (TPC), DPPH radical scavenging activity, texture and color. Predicted Keywords values for each of the responses were in good agreement with the experimental values. Seaweed concentration had most significant effect on phytochemical constituents of the breadsticks with Functional foods TPC and DPPH activity maximized when 17.07% H. elongata was incorporated into the flour Seaweeds Antioxidants (P < 0.05). An acceptable edible texture and color of breadsticks was also achieved at this Fiber concentration. Multiple response optimization demonstrated that phytochemical content of H. RSM elongata breadsticks may be maximized with dried seaweed and white flour concentrations of 17.07 and 21.89%, respectively, in the total flour. Total dietary fiber increased from 4.65 to 7.95% in the optimized sample, representing a 43.65% increase as compared to the control (P < 0.05). A sensory panel evaluated the acceptability of the seaweed breadsticks, as compared to the control, in terms of aroma, color, texture, taste and overall acceptability. There was no significant difference (P > 0.05) between the seaweed breadsticks and the control which shows that such fiber-rich seaweed bakery products are acceptable to consumers and have potential of increasing seaweed consumption among non-seaweed consumers. © All Rights Reserved Introduction fiber. The seaweed polysaccharides possess a higher Water Holding Capacity (WHC) than cellulosic Marine food, due to its phenomenal biodiversity fibers. There is an interest in seaweed hydrocolloids is a treasure house of many novel healthy food for human nutrition as they can act as dietary fiber ingredients and biologically active compounds such since their physiological effects are closely related to as those found in seaweeds. Despite having so many their physicochemical properties such as solubility, health benefits, marine functional foods have been viscosity, hydration, and ion-exchange capacities underexploited for food purposes. Bakery products in the digestive tract (Lahaye and Kaeffer, 1997). are widely consumed throughout the world and are Dietary fiber (DF) is the edible portion of plants the best sources of incorporating marine functional (or analogous carbohydrates) which is resistant to ingredients and reaching the targeted population digestion and adsorption in the human small intestine (Kadam and Prabhasankar, 2010). Bread is an excellent with complete or partial fermentation in the large product in which incorporation of ‘nutraceuticals’ is intestine (Gelroth and Ranhotra, 2001). The term attempted. One of the latest enrichments has been the DF comprises polysaccharides, oligosaccharides and addition of omega-3 PUFA to improve essential fatty associated plant compounds (AACC, 2001). acid intake. In Europe, consumption of bread enriched Brown seaweeds are known to contain more with omega-3 PUFA is steadily increasing because bioactive components than red or green seaweeds Europeans recognise the healthy component of such (Seafoodplus, 2008). Some of the bioactive products. Therefore, the near future for nutrition compounds identified in brown seaweeds include could potentially include extending the use of breads phylopheophylin, phlorotannins, fucoxanthin and as vehicles for different micronutrients (Kadam and various other metabolites (Hosakawa et al., 2006). Prabhasankar, 2010). Such antioxidants from natural sources can be added Seaweed contains a significant amount of soluble to products as an ingredient to increase the quality polysaccharides, and has potential function as dietary and shelf-life which also considerably enhances the *Corresponding author. Email: [email protected] Tel: +353 1 402 7570; Fax: +353 1 878 8978 1538 Cox, S. and Abu-Ghannam, N./IFRJ 20(4):1537-1545 consumer preference (Farag et al., 2003). with VWR Enviro-meter digital anemometer (VWR, Development of functional foods is currently Ireland). The dried seaweed was then ground into a one of the most intensive areas of food product fine powder using a blender (Rotor, Germany). development worldwide. Product optimization is an effective strategy to accomplish successful Experimental design development of the product with respect to a number To investigate the effect of factors (seaweed of attributes. If a food product cannot be re-engineered and white flour concentration) on phytochemical or modified to fulfill consumer desires and demand constituents, color and texture of breadsticks, a for the product, it will not succeed (Robinson, 2000). central composite design with two factors was The present study aimed to identify a food-based utilised. The central composite design was applied application for dried edible Irish seaweed in order to using STATGRAPHICS Centurion XV software encourage consumption amongst non-seaweed eaters. (StatPoint Technologies, Inc., Warrenton, VA, USA). The idea was to scientifically evaluate and improve The total number of experiments generated from the the quality and nutritional content of a bakery product software with two factors was 10 (= 2k + 2k + 2), upon the incorporation of seaweeds. Wheat is the where k is the number of factors. Eight experiments principal cereal used in the preparation of a variety of were augmented with two duplicates at the centre bakery products, however there is a current trend to points. The level of codes for the independent move away from white breads towards whole grains variables are presented in Table 1. The design matrix such as whole meal flour. Therefore in the present and variable combinations of seaweed and white study, white flour concentration was also varied and flour concentrations in experimental runs are shown the overall flour consisted of varying levels of dried in Table 2. The independent variable concentrations seaweed, white and wholemeal flours. The main applied in the response surface methodology objective was to optimize the dried seaweed and white (RSM) study (Seaweed 5 - 15% and white flour 10 flour concentrations in the development of a new - 30%) were percentage of the of the overall flour bakery based functional product and to investigate its concentration, with wholemeal flour making up effect on the phytochemical content of breadsticks. the remaining quantity up to 100%. Therefore as a percentage of the overall mix of 411 g, these values Materials and Methods consisted of 1.82 - 10.33 and 3.65 - 20.67% (seaweed and white flour, respectively). Chemicals 2, 2-Diphenyl-1-picrylhydrazyl (DPPH), Folin- Table 1. Level of codes for independent variables used in Ciocalteu’s phenol reagent, gallic acid, sodium the central composite design Independent variables Symbol -2 -1 0 +1 +2 carbonate (Na2CO3) and total dietary fiber kit were purchased from Sigma Aldrich Chemie (Steinheim, Seaweed concentration (%)* X1 2.93 5 10 15 17.07 Germany). White flour concentration (%)* X2 5.86 10 20 30 34.14 *Percentage of overall flour concentration (100%) with the remaining flour consisting of wholemeal Seaweed material H. elongata was purchased from Quality Sea Veg., Table 2. Design matrix and variable combinations in Co Donegal, Ireland. The seaweeds were collected experimental runs in October 2011 and stored at 4°C until further use. Experiment Seaweed concentration (%)* White flour concentration (%)* 1 15.00 10.00 Preparation of samples 2 10.00 20.00 H. elongata was washed thoroughly with tap 3 5.00 30.00 water to remove epiphytes and salt, dried with 4 10.00 20.00 5 17.07 20.00 absorbent paper and then cut into 3 cm long pieces 6 10.00 5.86 before dehydration. 7 5.00 10.00 Dehydration procedure 8 2.93 20.00 Drying temperature and time was decided based 9 10.00 34.14 10 15.00 30.00 on results of our previous kinetic experiments (Gupta *Percentage of overall flour concentration (100%) with the remaining flour consisting et al., 2011). Seaweed samples (5 g) were placed on a of wholemeal drying tray in a single layer. Drying of seaweed was Experimental data from the central composite carried out in a drier (Innova 42, Mason Technology, design was analysed and fitted to a polynomial Ireland) at 40°C air drying temperature over a period regression model below: of 24 hours. Air velocity was 2.0 ± 0.1 m s-1 measured Cox, S. and Abu-Ghannam, N./IFRJ 20(4):1537-1545 1539 2 2 Y = β0 + β1 χ 1 + β2 χ 2 + β11 χ 1 + β22 χ 2 + β12 χ 1 χ 2 Eq. 1 then extracted with 50 ml of methanol (60%) under nitrogen atmosphere for 2 hours as described by Cox Where; Y is response calculated by the model: β0 is et al. (2010). a constant and βi, βii and βij are linear, squared and interaction coefficients, respectively. Total phenolic content The adequacy of the model was evaluated by the The total phenolic concentration was measured lack of fit, coefficient of determination (R2) and the using the Folin-Ciocalteau method as outlined by Fisher’s test value (F-value) obtained from the analysis Cox et al. (2012). The total phenolic contents were of variance (ANOVA) generated by the software. expressed as mg gallic acid equivalent per 100 gram Statistical significance of the model and model dry basis (db) (mg GAE/100 g db).